body {
    font-family: sans-serif;
    text-align: center;
    padding: 2em;
  }
  
  .input-group {
    margin-bottom: 1em;
  }
  
  #new-task-input {
    width: 60%;
    padding: 0.5em;
  }
  
  #add-task-btn {
    padding: 0.5em 1em;
  }
  
  #task-list {
    list-style: none;
    padding: 0;
    max-width: 400px;
    margin: auto;
  }
  
  .task-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #f9f9f9;
    padding: 0.5em 1em;
    margin-bottom: 0.5em;
    border-radius: 4px;
  }
  
  .task-item.completed .task-text {
    text-decoration: line-through;
    color: gray;
  }
  
  .task-text {
    flex-grow: 1;
    margin-left: 1em;
  }